1. Field of the Invention
The present invention pertains to a lid cover for containers, and more particularly, to a venting lid cover adapted for use with drum containers (e.g., barrels) which may need vented assistance.
2. Description of the Related Art
Hazardous chemicals are often contained in drum containers and the vapors that emanate from the drum barrel openings (referred to as bung holes) must be controlled. One vapor control method includes placing the drum in an exhausted cabinet having an evacuating device. This generally requires that a large volume of ambient air be exhausted from the drum containers using a cabinet containing the drums. This is an inefficient operation due to the large sized air handling and removal equipment. Indeed, most of the vapors from a drum container are emitted only from the drum bungs when the drum is opened.
Another vapor control approach, that reduces the size of required equipment, is a separate lip exhauster device that is attached to the drum at each bung. This typically is an in-house solution and requires separate exhaust ducting to each bung hole that attaches with a fastener to the drum lid coaming (lip). This approach is cumbersome and inefficient since the fastener has to be affixed to the drum lip which in turn reduces operator access to the bung hole when making a connection.
Another approach includes a drum dome exhaust system that attaches to the top of a drum lid, which is transparent and has an exhausted dome that covers the entire drum. Such a system, referred to as a chemical dispense unit, is made by the BOC Edwards, Inc. of Wilmington, Mass., USA. Problems with this type of system include the need for drum connectors and associated duct piping that have to penetrate the dome. This in turn requires the operator to make the drum connections via hand-ports through the dome. Also, the dome requires a mechanism for lifting the dome up and out of the way to install and remove the drum container during transfers.
Of these approaches, the chemical drum exhaust cabinet is the most widely used system for vapor exhausting of drum containers. This system typically houses 55-gallon drum containers in the exhaust cabinet. Such a system is expensive at initial installation and expensive to operate (e.g., average use: 1000 cfm @ $3/cfm/yr equates to about $3K/yr). This system requires experienced operators who must be aware of and follow stringent safety requirements since many of the chemicals contained in the drums are either corrosive, hazardous or carcinogenic. For example, typical chemical agents used by a semiconductor manufacturer may include sulfuric acid, nitric acid, hydrochloric acid, hydrofluoric acid, ammonium hydroxide, plating solutions, etc.
Vent covers known in the container arts include U.S. Pat. No. 6,085,664, which discloses a vented hatch cover for a container having a hatch with a coaming surrounding the hatch opening. This cover is specifically designed for a railroad hopper car, which has a very different design compared to drum containers.
Thus, there is need for a drum container venting device that provides ease of use, yet inexpensively meets stringent safety requirements for personnel handling hazardous materials.
In accordance with the present invention, disadvantages and problems associated with previous venting devices and systems that handle hazardous materials in drum containers have been substantially reduced or eliminated. The present invention provides a venting lid cover that can be implemented with ease. The invention provides safety to personnel who handle hazardous materials in these containers.
To attain this objective, there is provided, according to one aspect of the invention, a venting lid cover that fits and xe2x80x9csnapsxe2x80x9d over the coaming (drum lip) of a drum container lid (e.g., a standard 55-gallon drum). The invention has particular use with drum containers holding hazardous chemical agents that must be properly vented when being transferred. The venting lid cover is constructed of a plate member with an attached plenum member that xe2x80x9csnaps-onxe2x80x9d the coaming of container lid. The plate has cutouts that allow the bung holes to pass through. Integral with the plenum member is an exhaust outlet port that attaches to the exhaust ducting. The plenum member attaches to the plate and has openings equal in number to bung holes of the container it operates with. The plenum member has vapor inlet ports that allow vapors from the bung holes to enter, that in turn exit through the exhaust outlet port. An external exhauster device attaches to the exhaust ducting, which can either be part of the ducting or a separate remote device of the facility. When the drum bung holes are open and the invention is installed on the lid of the container, any chemical vapors from the container are drawn into the exhaust ducting via the plenum member and removed from the facility safely and efficiently.
The invention provides many advantages over the conventional approaches as discussed above. Indeed, the venting lid cover is a separate reusable device that can be refitted and reused in a simple manner, with the invention self-alignment provided by the holes in the plate member that align with the bung holes on the top of a drum lid. The invention also allows different chemicals to be stored in standard sized drums without concern for contamination since the invention""s venting lid cover never contacts the chemical agents in the container. Additionally, if required, the venting lid cover can be configured permanently to a stationary container since the design is rugged and reliable. The invention also allows operators the freedom of not having to wear respirators when making connections of the containers. In certain applications, the invention also eliminates the need for continuous exhausting of vapor from a stationary container stored in a facility when the bung holes are closed. The invention provides the added freedom on locating the transfer site for the container since complex ducting is not required. Finally, the invention obviates the need for complex exhaust cabinets for working with drum containers which in turn minimizes the size required for the exhauster device (e.g. fan or equivalent pumping device).
Thus, it is an object of this invention to provide a venting lid cover for a container that has a plate member that can configurably seal with the coaming of the container, and a plenum member that attaches to this plate member. The plate member has at least one plate opening that equals the number of bung holes in the container so that the bung holes can pass through the plate. The plenum member has vapor passage openings that are equal in number and configured next to these plate openings.